I'm far, far behind and a few months back, I wish I had been here when questions were being asked about FIRS, but I'll provide them here now in case anybody is listening
A question about power stations and windmills: what will they do to enhance the game? Power plants often aren't built anywhere near cities, so the chain of Coal Mine -> Power Station results in transporting coal and the resulting production of electricity just disappears into nowhere. Power plants don't provide additional growth for nearby towns or industries, and you cannot transport it. Although there are a lot of products that disappear into thin air (construction supplies, food, vehicles) at least with those products they have to be sent to an end point, usually a city or a resort. As pretty as the sprites are, if FIRS cannot use the output of electricity to enhance the growth of town and other nearby industries, then perhaps it should be left out.
About oil wells & oil platforms: I like the in-land oil wells, but after the late 1800s the industry moved to overland/underground pipelines to transport from the wells to refineries, very little crude oil is moved from inland wells via vehicles. I could support the idea of having a refinery generating refined products on its own since we can't build pipelines. However, water-based oil platforms often don't have pipelines that connects them to the refineries, and ships will be required to take the product to shore. That said, though, ships usually do not transport to a collection point that requires the oil to be transported by vehicle, if there isn't a refinery right there at the dock to take the oil, then it's transported via pipeline to a refinery. In this case, however, since again we can't build pipelines, you could have trains/vehicles deliver to a refinery and boost its production.
The exception to this would be power plants that accept oil as part of their fuel sources. But, if you take my above suggestion and eliminate power plants if their production cannot be use, that's a moot point.
As an aside, oil wells often also produce natural gas. More and more frequently this gas is being captured rather than burned off to supply the ever-increasing natural gas market in order to capitalize on the "free stock" that's created as a byproduct of oil production. Possibility of creating a new chain from that ends up with a product that can realistically be used. If it's not refined into another product that is used in another chain, it can be distributed to natural gas power plants, engineering supplies for factories, and now even directly to consumers to home heating and fueling NG vehicles. That could be a very "green" and progressive chain. Although, that might complicate things a little.
On the Waste chain: Yes, I absolutely love it, because it is so realistic. This doesn't need to be in "basic" FIRS but should definitely be an add-on that can enhance so much. In addition to providing recycled scrap materials, garbage dumps can produce methane gas and incinerators can produce steam, both of which can be fed back into any industries which require products to either produce power or consume power as part of the manufacturing process.
I think separating everything out into economies was a great way to go, and probably should have been suggested a long time ago. Maybe not even focus this on "basic" and "extreme" FIRS, but just break each economy out into its own individual set: mining / industry, farming / food, waste / recycling.
Enough of my rambling I suppose
